3.7java中输入输出文件读取

import java.io.Console;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.Scanner;

public class Inputoutput {
    public static void main(String[] args) throws  IOException {

   /*     Scanner in = new Scanner(System.in);
        System.out.println("what is your name");
        String name = in.nextLine();
        System.out.println("how old are you");
        int age =in.nextInt();

        System.out.println("名字"+name+",年龄"+age);*/

        //控制台密码输入
        Console cons = System.console();
        if (cons != null) {
            String username = cons.readLine("username");
            char[] passwd = cons.readPassword("pwd");

            System.out.println("用户:" + username + ",密码:" + passwd);
        }

//        格式化输出
        double x = 10000.0 / 3.0;
        System.out.println(x);
        System.out.printf("%8.2f",x);
        System.out.printf("%b",x);

//        文件读取

        Scanner in = new Scanner(Paths.get("D:\\javaStudy\\day02\\src\\myfile.txt"),"UTF-8");
        try{
            while (true){
                String s = in.nextLine();
                System.out.println(s);
            }
        }
        catch (Exception e){
            e.printStackTrace();

        }
    }
}